Narrow L-dependent peaks commonly occur in the energy spectra of electrons precipitating from the inner radiation belt at L≈1.5-1.85, and the cause of the peaks has been attributed to cyclotron resonance interations with waves generated by VLF transmitters. In the slot region, L-dependent peaks have also been reportd at L≈2-3.5, but these have been predominately wider and consistent with their origin being cyclotron resonance interactions involving naturally occurring hiss. Here we investigate the innfrequent occurrence of narrow peaks in electrons precipitating at L>2. From coordinated wave and plasma density measurements it is found that if the narrow peaks are formed by first-order cyclotron resonant interactions occurring close to the magnetic equator between narrow band waves and the trapped electron poopulation then the equatorial plasma density gradients are unusually steep. This findinng is consistent with the evidence previously obtained by other techniques for structured plasma density profiles in that L shell region of space.